Oil-based muds form a general class of materials that minimally comprise a mixture of particulate solids in a hydrocarbon fluid. A subset of oil-based muds is oil-based drilling muds that contain functional additives used to improve drilling operations in several ways. These fluids are circulated through and around the drill bit to lubricate and cool the bit, provide suspension to help support the weight of the drill pipe and casing, coat the wellbore surface to prevent caving in and weight to balance against undesirable fluid flow from the formation, and to carry drill cuttings away from the bit to the surface. Such oil-based drilling fluids are oil-continuous compositions that may also contain an water solution (e.g. calcium chloride brine) as a discontinuous phase (making the fluids water-in-oil invert emulsions), emulsifiers to stabilize the invert emulsion, rheology modifying agents (e.g. oleophilic clays), weighting agents (e.g. barium sulfate), fluid loss control agents (e.g. lignins), and other additives (e.g. lime). Oil-based muds are water-in-oil macroemulsions, which are also called invert emulsions. Used oil-based drilling muds will contain, in addition to the above components, drill cuttings and other dissolved or dispersed materials derived from the drilled medium or from other sources of contamination such as process and environmental waters. With high levels of contamination, oil-based drilling muds lose their desirable fluid properties and performance. As a consequence, contaminated oil-based muds must be discarded or reconditioned.
The present disclosure addresses the reclamation and recycling of such fluids.